When feeding piece articles from a bulk to the production equipment work site, the need arises to extract the articles piece by piece and, having arranged them in the preset position, transport them to other actuators, which manipulate the articles according to the predetermined program.
Articles with the length-to-diameter ratio (l/d) exceeding 6 are referred to as long articles. Being heaped up in a hopper, such articles form stable bridges in the operating area of the extracting means, which breaks the rhythm of extraction and feeding of articles to the production equipment. Therefore, prior art apparatuses use energetic agitation of all articles contained in the hopper, as by shaking, vibration and scattering, which is conducive to damage of the surface of articles and to excessive noise. Moreover, the dimensions of the hopper in prior art apparatuses are restricted by the conditions under which the extracting means are capable of piece-by-piece separation of articles from a bulk. Also, said prior art apparatuses have a high-positioned hopper, essential for obtaining the requisite difference in heights between the charging and feeding levels, which is a major inconvenience in operation. It is noteworthy that the larger the dimensions of the articles being charged into the hopper, the larger the overall dimensions and working height of the latter, which impedes charging; on the other hand, the necessity for piece-by-piece feeding of articles into the hopper causes additional inconveniences in operation.
Known in the art are elevator-type charging apparatuses with chain conveyers and low-positioned hoppers. A disadvantage of such apparatuses, however, is also the possibility of a bridge being formed in handling long articles, whereas use of agitators causes damage to the surface of articles and generates excessive noise. Such apparatuses allow only simple-shaped articles to be extracted from a bulk and fed therefrom.
Also known in the art is a screw conveyer (USSR Inventor's Certificate No. 597,608, Int. cl. B 65 G 33/24, 1978), comprising a means for extraction of piece articles bulked in a hopper, made in the form of a gripping and a conveying screws, arranged parallel to which are members for holding of articles in the preset position during transportation, made in the form of ratchet teeth provided on the inner surface of the transporting tube, with the teeth projections at the tube inlet, made on the arcs of circumferences, diminishing towards the tube end.
Disadvantages of said apparatus are:
the gripping screw being made in the form of an individual member - the agitator, acting only upon the lower layer of the articles pressed down by the upper ones, imposes great loads upon these articles, thereby causing damage to the surface thereof;
variation of the cross-section of the inner surface of the transporting tube from its end to transportation channels in the sense of reduction gives rise to conditions favourable for the articles to be squeezed between the screw and the teeth projections;
absence of initial orientation;
the articles being enclosed in the tube during the entire transportion route hampers servicing of the apparatus, as there is no possibility of quick location of the jamming spot and establishing the cause of the apparatus failure.
Furthermore, said prior art apparatus makes it possible to extract and feed articles only of simple shapes, e.g. washers, caps, rings and the like, whose length (height)-to-diameter ratio does not exceed one (l/d&lt;1). Long articles cannot be charged with the aid of said apparatus due to formation of a stable bridge before the inlet to the transporting tube.
An object of the present invention is to obviate said disadvantages of the foregoing apparatuses.